P1391 for 04' SRT-10

[Moose82169]

P1391 for 04\' SRT-10

I'm trying to get help for a guy at another forum. Here is his problem:

Hi all,
I am trying to help a friend out. He got stuck yesterday, the SES light came up with code P1391. He has a 2004 Viper. Is it the crankshaft sensor that needs to be replaced? How big of a job would that be?
Any advice would be greatly appreciated.
Thanks

--John

http://www.dodgeforum.com/m_292733/tm.htm